SOS, CQD and the History of Maritime Distress Calls To Telegraph Office Main Page Welcome back to the Telegraph Office. This month we are going to diverge a little from talking about wire and wireless artifacts and talk about wireless telegraph distress signals. Mystery, intrigue as well as misinformation surrounds the origin and use of maritime distress calls. The general populace believes that "SOS" signifies "Save Our Ship." Casual students of radio history are aware that "CQD" preceded the use of "SOS." Why were these signals adopted? When were they used? Why did one replace the other? What is one likely to find by digging a little deeper? The practical use of wireless telegraphy was made possible by Guglielmo Marconi in the closing years of the 19th century. Until then, ships at sea out of visual range were very much isolated from shore and other ships. A ship could vanish from the high seas, and no one would know until that vessel failed to make a port connection. Marconi, seeing that wireless would not compete with wire telegraphy for land based communication, concentrated his efforts on ship to shore communications. Ships equipped with wireless were no longer isolated.

The first use of wireless in communicating the need for assistance came in March of 1899. The East Goodwin Lightship, marking the southeastern English coast, was rammed in a fog in the early morning hours by the SS R. F. Matthews. A distress call was transmitted to a shore station at South Foreland and help was dispatched. By 1904 there were many Trans-Atlantic British ships equipped with wireless. The wireless operators came from the ranks of railroad and postal telegraphers. In England a general call on the landline wire was a "CQ." "CQ" preceded time signals and special notices. "CQ" was generally adopted by telegraph and cable stations all over the world. By using "CQ," each station receives a message from a single transmission and an economy of time and labor was realized. Naturally, "CQ" went with the operators to sea and was likewise used for a general call. This sign for "all stations" was adopted soon after wireless came into being by both ships and shore stations. At the first international congress of wireless telegraphy in 1903, the Italians recommended the use of "SSSDDD" to signal an emergency.

"D" had previously been used internationally as the signal for an urgent message. The origin of "S" is not known, but it may have come from the first letter of the word ship, indicating a ship in distress. The sending of "SSSDDD" would signal all other stations to stop sending and leave the channel open for emergency traffic. Though discussed, it was not adopted. Deciding on a distress signal was put on the agenda for the next meeting in 1906. "DDD" would later be adopted for the silent signal, indicating all stations must cease sending. In 1904, the Marconi company filled the gap by suggesting the use of "CQD" for a distress signal. It was established on February 1 of that year by Marconi Company's circular No. 57. Although generally accepted to mean, "Come Quick Danger," that is not the case. It is a general call, "CQ," followed by "D," meaning distress. A strict interpretation would be "All stations, Distress." In the U.S.

Senate hearings following the Titanic disaster, interrogator Senator William Smith asked Harold Bride, the surviving wireless operator, "Is CQD in itself composed of the first letter of three words, or merely a code?" Bride responded, "Merely a code call sir." Marconi also testified, "It [CQD] is a conventional signal which was introduced originally by my company to express a state of danger or peril of a ship that sends it." At the second Berlin Radiotelegraphic Conference of 1906, the subject of a distress signal was again addressed. The distress signal chosen was "SOS." (The American distress signal "NC" for "Call for help without delay" was not adopted, although it remains as the international flag symbol for distress to this day.) Popular accounts portray the adoption of "SOS" as being derived from "SOE," which the Germans had used as a general inquiry call. These accounts suggest there was objection because the final letter of "SOE" was a single dot, hard to copy in adverse conditions. The letter "S" was substituted accounts say, for three dots, three dashes and three dots could not be misinterpreted.

Popular accounts of the origin of "SOS" fail to mention that the Germans had used "SOS" for a distress signal. They adopted the signal "SOS" for distress as well as "SOE" for inquiry on April 1, 1905, a year before the Berlin conference. The Electrician, May 5, 1905 published "German Regulations for the Control of Spark Telegraphy" which stated: "...---..., "Distress" signal (Notzeichen). This is to be repeated by a ship in distress until all other stations have stopped working." Unfortunately, the 1906 Conference proceedings do not give an account of the discussions nor the origin of SOS. The proceedings merely specify what the signal will be. In the Service Regulations Affixed to the International Wireless Telegraph Convention, paragraph 6a, "Signals of Transmission" states:: "Ships in distress shall use the following signal: ...---... repeated at brief intervals." The Marconi Yearbook of Wireless Telegraphy and Telephony , 1918 states, "This signal [SOS] was adopted simply on account of its easy radiation and its unmistakable character.

There is no special signification in the letter themselves, and it is entirely incorrect to put full stops between them [the letters]." All the popular interpretations of "SOS," "Save or Ship," "Save Our Souls," or "Send Out Succour" are simply not valid. Stations hearing this distress call were to immediately cease handling traffic until the emergency was over and were likewise bound to answer the distress signal. Although the use of "SOS" was officially ratified in 1908, the use of "CQD" lingered for several more years, especially in British service where it originated. It is well documented in personal accounts of Harold Bride, second Radio Officer, and in the logs of the SS Carpathia, that the Titanic first used "CQD" to call for help.

When Captain Smith gave the order to radio for help, first radio officer Jack Phillips sent "CQD" six times followed by the Titanic call letters, "MGY." Later, at Brides suggestion, Phillips interspersed his calls with "SOS." In SOS to the Rescue, 1935, author Baarslag notes, "Although adopted intentionally in 1908, it [SOS] had not completely displaced the older "CQD" in the British operators' affections." Marconi in his U.S. Senate testimony on the Titanic disaster said, "I should state that the international signal [SOS] is really less known that the Marconi Co.'s [CQD] signal." (It is interesting to observe that Marconi was waiting in New York to return home to England on the Titanic.) The first use of wireless in the rescue of an American ship was in 1905. Off Nantucket, the operator of Relief Ship No. 58, a light ship, sent "HELP" in International Morse and American Morse. (Trans-Atlantic ships used International Morse and coastal ships used American Morse.

The use of American Morse on seagoing vessels ceased in 1912 although it survived for many years on the Great Lakes.) A Naval Radio Station in Rhode Island answered the "HELP" call. The rescue of 1,500 passengers and crew from the Republic and the Florida by the Baltic in January of 1909, was the defining moment in wireless rescue history. The White Star liner Republic was rammed in a dense fog by the Italian Florida. Wireless operator Jack Binns of the Republic, sent out a "CQD." (The Florida was not wireless equipped.) The Baltic came to the rescue after hunting for the Republic in the fog for many hours. Those concerned with the maritime industry now realized the importance of equipping ships with wireless. The number of ships equipped with wireless grew rapidly after the Republic disaster. For example, at the end of 1909 the Marconi Co. owned and operated 143 wireless stations on the high seas. By the summer of 1911, the number grew to 303 stations. By the end of 1912, there were 580 shipboard wireless installations. The U.S.

Department of Commerce, Bureau of Navigation publication, Important Events in Radio telegraphy, 1916, recorded maritime disasters in which wireless played a part in rescue on the seas and the Great Lakes. From 1899 to 1908, there were nine such events. In 1909 there were 18 rescues and in 1915, 35 rescues. The following quote, though not directly rescue related, demonstrates the extreme importance of shipboard wireless: "November, 1914 -- Great Lakes storms destroyed 19 vessels, none of which were equipped with wireless. All vessels having radio apparatus installed received warning of the coming storm and sought safety." The first recorded use of "CQD" by an American ship was in 1908 by the steamer Santa Rosa off the coast of California. Commander Richard Johnstone records this in his memoir My San Francisco Story of the Waterfront and the Wireless, 1965. The first recorded American use of "SOS" was in August of 1909. Wireless operator T. D.

Haubner of the SS Arapahoe radioed for help when his ship lost its screw near Diamond Shoals, sometimes called the "Graveyard of the Atlantic." The call was heard by the United Wireless station "HA" at Hatteras. A few months later, the SS Arapahoe received an "SOS" distress call from the SS Iroquois. Radio Officer Haubner therefore has the distinction of being involved in the first two incidents of the use of "SOS" in America, the first as the sender and the second as the receiver. Being slow to adopt international wireless standards, the U.S. did not officially adopt "SOS" until 1912. Besides "CQD" and "SOS," "XXX" was used as an urgent signal, being less urgent than "SOS." "XXX" was used when there was concern for the safety of a ship or the safety of person on board or a person sighted from on board. "TTT" was used as a safety signal to precede ice, storm and other navigational warnings including coastal artillery practice. "MEDICO" was used by ships without a doctor seeking medical advice from another ship or shore station.

During W.W.II, the signal "SSSS" was used for "submarine sited". The distress call by radio telephone is the two words "MAY DAY." This corresponds to the French pronunciation for "m'aider", which means "help me." On voice, the "XXX" (urgent) equivalent is the word "PAN." This corresponds to the French pronunciation for "panne", which means "mishap" or "accident." The "TTT" (safety) equivalent is "SECURITY." This corresponds to the French pronunciation for "sécurité", which means "safety." The calling frequency for voice was 2182 kilohertz. During the investigation into the Titanic disaster, Guglielmo Marconi stated that he was experimenting with a device that could be used as an automated alarm for distress signals. Upon hearing a series of signals, an alarm bell would ring. Some European nations put these alarms into service. A sequencing device was connected to the output of the receiver. Upon the reception of four or more dashes of exactly four seconds duration, a device rang an alarm bell in the radio shack, the radio officer's quarters and on the ship's bridge.

The system was employed as a substitute for a second operator. Because the system could miss a call under adverse conditions or ring the bell in error, American radio authorities deemed it unreliable and not a substitute for another on duty operator. Americans later mandated the used of automatic alarms with the Communications Act of 1934. At the third international radiotelegraph conference in 1912, it was agreed that ships would listen for distress signals on a wavelength of 600 meters. This is a frequency of about 500 kilohertz. (The calling and distress frequency for the Great Lakes was 410 kilohertz.) International law required each ship to cease transmitting for three minutes at 15 and 45 minutes past the hour. During this interval they were required to listen for distress calls. At this conference, the recent Titanic disaster was fresh on the minds of the delegates, particularly the British. Consequently, many advances were made concerning the cooperative use of wireless for safety at sea. It is interesting that the use of "CQ" as a general call was displaced by "QST" in 1911. Radio amateurs, or hams as they are more commonly called, continue to use both.

"CQ" is used as "calling any station" and "QST" is used as "calling all stations" Wireless and radio literature of the early and mid 20th century is rich in documenting the use of maritime distress signals. Only the surface of the subject is covered here. Yet, perhaps next time a reference to "SOS" is seen, there will be a little more appreciation of its lineage. Special thanks to Thomas White for providing electronic copies of German Regulations for the Control of Spark Telegraphy, Important Events in Radiotelegraphy and International Wireless Telegraph Convention. Without them, this article would not have been complete. Bibliography Baarslag, Karl. SOS to the Rescue. New York: Oxford University Press, 1935. DeNeuf, Don. SSSDDD? SOE? CQD? SOS?. Telecommunications, Old Timer's Bulletin, Vol. 30. No. 2, Antique Wireless Association, 1989. End of SOS Recalls Early Origins. Dots and Dashes - Official Publication of the Morse Telegraph Club, Inc. Vol. 27. No. 1, 1999.

"German Regulations for the Control of Spark Telegraphy." The Electrician, May, 1905. Hancock, H. E. Wireless at Sea, The First Fifty Years. Chelmsford, England: Marconi International Marine Communications Company, 1950. Important Events in Radiotelegraphy, Department of Commerce, Bureau of Navigation, Radio Service, Washington: G.P.O., 1916. International Wireless Telegraph Convention. Washington: G.P.O., 1907. Johnstone, Richard. My San Francisco Story of the Waterfront and the Wireless. Larkspur, California: Richard Johnstone, 1965. Kuntz, Tom. (editor) The Titanic Disaster Hearings: The Official Transcripts of the 1912 Senate Investigation. Pocket Books, 1998. "Marconi's Latest -- Wireless Distress Signal That Rings a Bell -- Titanic Commission Hears of New Invention." Daily Sketch (British newspaper) 19 June 1912. from The Titanic Disaster - As Reported in the British National Press April - July 1912. compiled by Dave Bryceson.

New York: Norton, 1997 Morgan, Alfred P. Wireless Telegraphy and Telephony. New York: Henley, 1920. Nilson, Arthur R. and Hornung, J. L. Radio Operating Questions and Answers. New York: McGraw-Hill, 1940. Olson, Hank and Orr, Bill. The KFS-Federal-MacKay Story: From CW Arc to Silicon Valley. The AWA Review, Vol. 8, 1993. Schroeder, Peter B. Contact at Sea, A History of Maritime Radio Communications. Ridgewood, N.J.: The Gregg Press, 1967. Strichartz, M. H. Marine Radio Manual. New York: Cornell Maritime Press, 1944 The Year-Book of Wireless Telegraphy & Telephony 1918. London: The Wireless Press, LTD., 1918. Image Collins, Francis A. The Wireless Man His Work and Adventures on Land and Sea (Boy Scout edition).

Grosset & Dunlap, 1912 SOS - The Universal Distress Signal By Jennifer Rosenberg Updated September 30, 2015. While "SOS" is an easily recognizable term now, there wasn't always an internationally recognized distress call. It was at a Radiotelegraphic Conference held in Berlin in 1906 that a need for one was recognized and chosen. However, it wasn't until two years later, July 1, 1908, that the International Morse Code signal "SOS" (three dots, three dashes, and then three dots) became the official distress call around the world. Morse Code For centuries, ships became isolated as soon as they left visual range of shore and of other ships. This meant that if a ship encountered any problems while at sea, they could sink without anyone knowing their fate. This isolation ended with the invention of the wireless telegraph and Morse Code. Morse Code , invented in the 1830s in the United States by Samuel Morse , assigned a series of dashes and/or dots to each letter of the alphabet. These could then be transmitted over an electric telegraph and be deciphered on the other end.

continue reading below our video Test Your General Science Knowledge As truly revolutionary as Morse Code was at the time, it was not able to be used internationally since it did not account for letters that had diacritic marks (such as acute, umlaut, or hacek). To correct this failing, a conference was held in Europe in 1851, which created the International Morse Code (sometimes called the Continental Morse Code). Now that there was a universal code that all sailors could know and learn, it was time to create a universal distress call. CQD - The First Distress Call By 1904, many transatlantic ships had wireless telegraph capability on board. Realizing a need for a widely recognized distress call, the letters "CQD" became the first distress call. At the time, both on land and at sea, the letters "CQ" preceded any general message meant for all stations. Thus "CQD" means "All stations, distress." (It was not "Come Quick Danger" as some will report.) At the Radiotelegraphic Conference held in Berlin in 1906, it was noted that there needed to be an internationally agreed upon and recognized signal for distress.

No longer should Great Britain use "CQD" while Germany used "SOE." A single distress call was needed. SOS After much discussion, the letters "SOS" were agreed upon. Although many have later stated that the letters stand for "Save Our Ship," "Save Our Souls," "Sink or Swim," or "Send Out Succor," this is not true. The letters were chosen for the ease and unmistakability of three dots, three dashes, and three dots and not for the actual letters of "SOS." After being agreed upon at the 1906 conference, the Morse code signal of three dots, three dashes, and then three dots (sent together, without spacing) went into effect as the international signal for distress on July 1, 1908. The Titanic Although now officially the international signal for distress, many people still used the old signal of "CQD." Even in 1912, when the Titanic began to sink , its radio operator placed the "CQD" distress signal until another operator suggested to also send the new "SOS" signal. It took several years for "SOS" to replace the old signal.

Mayday When radios began to replace the telegraph, a different term was needed for a distress call. It had to be a word that would be easily understandable over the radio but that was not used regularly in day-to-day speech. The term "Mayday" (based on the French word "m'aidez," which means "help me") was selected in 1923 by senior London radio officer Frederick Stanley Mockford. Four years later, "Mayday" became the official voice distress call. To make sure it is clear, it is customary to say the word "Mayday" three times in a row when in distress. SOS Morse Code · International Standard Emergency Signal - YouTube SOS Morse Code · International Standard Emergency Signal Want to watch this again later? Sign in to add this video to a playlist. Need to report the video? Sign in to report inappropriate content. The interactive transcript could not be loaded. Loading... Rating is available when the video has been rented. This feature is not available right now. Please try again later. Published on Feb 11, 2016 Emergency video with standard Morse Code times, at a speed of 8 words per minute.

In an emergency, remember this video and leave it playing, is just another way of calling for help! :) In morse code, SOS is represented as: . . . - - - . . . The SOS distress signal was first adopted by the German government in radio regulations effective April 1, 1905, and became the worldwide standard under the second International Radiotelegraphic Convention, which was signed on November 3, 1906, and became effective on July 1, 1908. SOS remained the maritime radio distress signal until 1999, when it was replaced by the Global Maritime Distress and Safety System. SOS is still recognized as a visual distress signal. The SOS distress signal is a continuous sequence of three dits, three dahs, and three dits, all run together without letter spacing. In International Morse Code, three dits form the letter S, and three dahs make the letter O, so "SOS" became an easy way to remember the order of the dits and dahs. In modern terminology, SOS is a Morse "procedural signal" or "prosign", and the formal way to write it is with a bar above the letters.

In popular usage, SOS became associated with such phrases as "Save Our Ship" or "Save Our Souls" or "Send Out Succour". SOS is only one of several ways that the combination could have been written; VTB, for example, would produce exactly the same sound, but SOS was chosen to describe this combination. SOS is the only nine-element signal in Morse code, making it more easily recognizable, as no other symbol uses more than eight elements. What is the Meaning of SOS? - BoatSafe.com What is the Meaning of SOS? Harmony asks "Do the letters in the term SOS represent three words? If so could you let me know what they are?" Thanks to Neal McEwen for allowing us to use information from his article "SOS", "CQD" and the History of Maritime Distress Calls. There is much mystery and misinformation surrounding the origin and use of maritime distress calls. Most of the general populace believes that "SOS" signifies "Save Our Ship." Casual students of radio history are aware that the use of "SOS" was preceded by "CQD." Why were these signals adopted? When were they used?

The practical use of wireless telegraphy was made possible by Guglielmo Marconi in the closing years of the 19th century. Until then, ships at sea out of visual range were very much isolated from shore and other ships. The wireless telegraphers used Morse Code to send messages. Morse Code is a way of "tapping" out letters using a series of dots (short signals) and dashes (long signals). Spoken, short signals are referred to as "dih" and long signals are referred to as "dah". The letter "A" is represented by a dot followed by a dash: By 1904 there were many trans-Atlantic British ships equipped with wireless communications. The wireless operators came from the ranks of railroad and postal telegraphers. In England a general call on the landline wire was a "CQ." "CQ" preceded time signals and special notices. "CQ" was generally adopted by telegraph and cable stations all over the world. By using "CQ," each station receives a message from a single transmission and an economy of time and labor was realized. Naturally, "CQ," went with the operators to sea and was likewise used for a general call.

This sign for "all stations" was adopted soon after wireless came into being by both ships and shore stations. In 1904, the Marconi company suggested the use of "CQD" for a distress signal. Although generally accepted to mean, "Come Quick Danger," that is not the case. It is a general call, "CQ," followed by "D," meaning distress. A strict interpretation would be "All stations, Distress." At the second Berlin Radiotelegraphic Conference 1906, the subject of a danger signal was again addressed. Considerable discussion ensued and finally SOS was adopted. The thinking was that three dots, three dashes and three dots could not be misinterpreted. It was to be sent together as one string. The Marconi Yearbook of Wireless Telegraphy and Telephony , 1918 states, "This signal [SOS] was adopted simply on account of its easy radiation and its unmistakable character. There is no special signification in the letter themselves, and it is entirely incorrect to put full stops between them [the letters]." All the popular interpretations of "SOS," "Save Our Ship," "Save Our Souls," or "Send Out Succour" are simply not valid.

Stations hearing this distress call were to immediately cease handling traffic until the emergency was over and were likewise bound to answer the distress signal. Although the use of "SOS" was officially ratified in 1908, the use of "CQD" lingered for several more years, especially in British service where it originated. It is well documented in personal accounts of Harold Bride, second Radio Officer, and in the logs of the SS Carpathia, that the Titanic first used "CQD" to call for help.

When Captain Smith gave the order to radio for help, first radio officer Jack Phillips sent "CQD" six times followed by the Titanic call letters, "MGY." Later, at Brides suggestion, Phillips interspersed his calls with "SOS." In SOS to the Rescue, 1935, author Baarslag notes, "Although adopted intentionally in 1908, it [SOS] had not completely displaced the older 'CQD' in the British operators' affections." (It is interesting to observe that Marconi was waiting in New York to return home to England on the Titanic.) The first recorded American use of "SOS" was in August of 1909. Wireless operator T. D. Haubner of the SS Arapahoe radioed for help when his ship lost its screw near Diamond Shoals, sometimes called the "Graveyard of the Atlantic." The call was heard by the United Wireless station "HA" at Hatteras. A few months later, the SS Arapahoe received an "SOS" distress call from the SS Iroquois.

Radio Officer Haubner therefore has the distinction of being involved in the first two incidents of the use of "SOS" in America, the first as the sender and the second as the receiver. The U.S. did not officially adopt "SOS" until 1912, being slow to adopt international wireless standards. Related Articles: SOS - Wikipedia, the free encyclopedia SOS SOS in Morse code Problems listening to this file? See media help . SOS is the commonly used description for the international Morse code distress signal (· · · — — — · · ·). This distress signal was first adopted by the German government in radio regulations effective April 1, 1905, and became the worldwide standard under the second International Radiotelegraphic Convention, which was signed on November 3, 1906 and became effective on July 1, 1908. SOS remained the maritime radio distress signal until 1999, when it was replaced by the Global Maritime Distress Safety System . [1] SOS is still recognized as a visual distress signal.

[2] From the beginning, the SOS distress signal has actually consisted of a continuous sequence of three- dits /three- dahs /three-dits, all run together without letter spacing. In International Morse Code , three dits form the letter S, and three dahs make the letter O, so "SOS" became an easy way to remember the correct order of the dits and dahs. In modern terminology, SOS is a Morse " procedural signal " or "prosign", and the formal way to write it is with a bar above the letters, i.e. SOS. In popular usage, SOS became associated with phrases such as "save our ship" or "save our souls". These were a later development, most likely used to help remember the correct letters (a backronym ). As the SOS signal is a prosign , its respective letters have no inherent meaning per se, it was simply chosen due to it being easy to remember.[ citation needed ] Contents [ edit ] Formalization The use of the SOS signal was first introduced in Germany as part of a set of national radio regulations, effective April 1, 1905. These regulations introduced three new Morse code sequences, including the SOS distress signal.

In 1906, at the second International Radiotelegraphic Convention in Berlin, an extensive collection of Service Regulations was developed to supplement the main agreement, which was signed on November 3, 1906, becoming effective on July 1, 1908. Article XVI of the regulations adopted Germany's Notzeichen distress signal as the international standard, reading: "Ships in distress shall use the following signal: · · · — — — · · · repeated at brief intervals". The first ship to transmit an SOS distress call appears to have been the Cunard liner Slavonia on June 10, 1909, according to "Notable Achievements of Wireless" in the September, 1910 Modern Electrics. However, there was some resistance among the Marconi operators to the adoption of the new signal, and, as late as the April, 1912 sinking of the RMS Titanic , the ship's Marconi operators intermixed CQD and SOS distress calls. However, in the interests of consistency and water safety, the use of CQD appears to have died out after this point.

In both the April 1, 1905 German law, and the 1906 International regulations, the distress signal was specified as a continuous Morse code sequence of three-dits/three-dahs/three-dits, with no mention of any alphabetic equivalents. However, in International Morse, three dits comprise the letter S, and three dahs the letter O. It therefore soon became common to refer to the distress signal as "SOS." An early report on "The International Radio-Telegraphic Convention" in the January 12, 1907 Electrical World stated that "Vessels in distress use the special signal, SOS, repeated at short intervals." (In American Morse code , which was used by many coastal ships in the United States through the first part of the twentieth century, three dahs stood for the numeral "5", so in a few cases the distress signal was informally referred to as "S5S"). In contrast to CQD, which was sent as three separate letters with spaces between each letter, the SOS distress call has always been transmitted as a continuous sequence of dits-and-dahs, and not as individual letters.

There was no problem as long as operators were aware that "SOS" was technically just a convenient way for remembering the proper sequence of the distress signal's total of nine dits and dahs. In later years, the number of special Morse symbols increased. In order to designate the proper sequence of dits-and-dahs for a long special symbol, the standard practice is to list alphabetic characters which contain the same dits-and-dahs in the same order, with a bar atop the character sequence to indicate that there should not be any internal spaces in the transmission. Thus, under the modern notation, the distress signal becomes SOS. (In International Morse, VTB, IJS and SMB, among others, would also correctly translate into the · · · — — — · · · distress call sequence, but traditionally only SOS is used). It has also sometimes been used as a visual distress signal, consisting of three short, three long, three short light flashes such as from a survival mirror, or with "SOS" spelled out in individual letters, for example, stamped in a snowbank or formed out of logs on a beach. The fact that SOS can be read right side up as well as upside down became important for visual recognition if viewed from above.

[ edit ] Later developments Additional warning and distress signals followed the introduction of SOS. On January 20, 1914, the London International Convention on Safety of Life at Sea adopted the Morse code signal TTT ( — — —), three letter T's (—) spaced correctly as three letters so as not to be confused with the letter O (- - -), as the "Safety Signal," used for messages to ships "involving safety of navigation and being of an urgent character." With the development of audio radio transmitters, there was a need for a spoken distress phrase, and " Mayday " was adopted by the 1927 International Radio Convention as the equivalent of SOS. For TTT the equivalent audio signal is " Securité " for navigational safety. During the Second World War , additional codes were employed to include immediate details about attacks by enemy vessels, especially in the Battle of the Atlantic . The signal SSS signalled attacked by submarines, whilst RRR warned of an attack by a surface raider, QQQ warned of an unknown raider (usually an auxiliary cruiser ), and AAA indicated an attack by aircraft. They were usually sent in conjunction with the SOS distress code.

All of these codes later switched from three repeats of the letter to four repeats ("RRRR", etc.). None of these signals were used on their own. Sending SOS as well as other warning signals (TTT, XXX etc.) used similar procedures for effectiveness. These were always followed correctly. Here is an example of an SOS signal; the portions in brackets are an explanation only. SOS SOS SOS de (this is) GBTT GBTT GBTT (call sign of the QE2 repeated 3 times) Queen Elizabeth 2 (name of ship) psn (position) 49.06.30 North, 04.30.20 West. Ship on fire, crew abandoning ship (nature of distress) AR (end of transmission) K (invitation to reply). Ships and coastal stations would normally have required quiet times twice an hour to listen for priority signals. However, many merchant vessels carried only one or two radio operators in which case the SOS may not be heard by operators off duty. Eventually equipment was invented to summon off-duty operators by ringing an alarm in the operators berth. This was triggered by the operator of the ship in distress transmitting twelve long dashes of four seconds duration each.

These were sent prior to the SOS hopefully ringing the automatic alarm in ships so equipped. If possible a short delay was given before transmission of the SOS proper. This was to give those off watch operators time to get to their radio office. [ edit ] Cultural references S.O.S. is the title of a 1975 song by the Swedish pop group ABBA . The Delorean time machine, in the 1985 sci-fi/comedy film Back to the Future , flashed its headlights to this-during the climax; as the engine stalled, low on fuel . The same-named brand of kitchen scouring pads had a popular television commercial in 1994. Kitchen and tablewares alike all clinged and tapped the original jingle in unison, to signal being in need of the product. 2007 saw the famous Kool-Aid beverage mix air its "Singles" flavours. The commercial began with an aerial view of an island, advertising, "S.U.S.: Stirring Up Singles", on the sand below. Inviting those from a helicopter to try the individual packs. [ edit ] Famous SOS calls CQD - What does CQD stand for?

The Free Dictionary CQD - What does CQD stand for? The Free Dictionary Ciudades Que Danzan (Spanish: Dancing Cities) CQD Code Question of the Day CQD Cidades Que Dancam (Portugese: Cities That Dance) CQD Come - Quick - Danger/Distress (distress call used prior to SOS) CQD Como Queria Demonstrar (Portuguese: QED) CQD Cost, Quality, Delivery (supplier performance) CQD Conseil Quebecois de la Domotique (French; Canada) CQD Cargills Quality Dairies Limited (Sri Lanka) CQD CQD Case Quantity Discount Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: Write what you mean clearly and correctly. References in periodicals archive ?

1) For the first objective, firstly we will grow a stable inorganic semiconductor shell outside CQD core as the protecting layer; secondly, we will fill up the voids in CQD film using stable amorphous n-type TiOx or p-type MoO3 to cut off the way of oxygen attacking the exposed CQD surface. The proposed project aims to address two limitations of CQD SCs. CQD CQD CQD was the original standard international Morse code distress signal. It was originally proposed and adopted by Marconi on January 7 , 1904 . It was officially superseded with the code SOS in 1908 which was considered more distinctive and easier to use. The signal used by British radio operators for many years was CQD (based on the attention call CQ ), but there was no international standard. At the 1906 International Conference on Wireless Communication at Sea, it was resolved that SOS should be used as a distress call. Britain adopted this standard in 1908, but the radio operators retained their old habit of using CQD.

When the Titanic sank in 1912, its radio operator Jack Phillips initially sent the distress call as "CQD", but was reminded by Harold Bride, the junior radio operator that the new code was "SOS" and that he should send it, as it might be his "last chance to use it." Phillips then used both codes alternately. For some reason, people are under a mistaken belief that the sinking of the Titanic was the first use of the "SOS" call: it wasn't. However the news accounts of the Titanic disaster cemented the new "SOS" call in the mind of the public, and it began to be used regularly afterward. Fact-index.com financially supports the Wikimedia Foundation. Displaying this page does not burden Wikipedia hardware resources. This article is from Wikipedia . All text is available under the terms of the GNU Free Documentation License . SOS Facts for Kids | KidzSearch.com 5 References Early developments Before radio communication was developed in the early 1890s, seagoing ships had already adopted many different visual and audio distress signals. They used such things as semaphore flags , signal flares , bells , and foghorns . In the beginning, radio was called wireless telegraphy.

It used Morse code , the dit-and-dah system originally developed for landline telegraphy .When radio communication was made available to ships, there was a need for standardized communication. Cooperation was somewhat limited by national differences and rivalries between different radio companies. The first International Radiotelegraphic Conference was held in Berlin , Germany in 1903 . At the time, Captain Quintino Bonomo, an Italian representative, discussed the need for common operating procedures. He also had the suggestion that "ships in distress... should send the signal SSS DDD at intervals of a few minutes", according to "The Wireless Telegraph Conference", in the November 27 , 1903 , issue of The Electrician. Question on how to do things were beyond the scope of the 1903 Conference. Although Article IV of the Conference's Final Protocol, signed August 13 , 1903 , said that "Wireless telegraph stations should unless practically impossible, give priority to calls for help received from ships at sea," no standard signal was adopted at the time. Because there were no international regulations, each ship was left to develop its own practices.

For example in 1905 the crew of a sinking lightship off Nantucket transmitted the word "HELP" to call for rescue. Perhaps the first international radio distress call adopted was " CQD " ( — · — · — — · — — · · ). This was announced on January 7 , 1904 by "Circular 57" of the Marconi International Marine Communication Company. It became effective for Marconi installations on February 1 , 1904 . Another suggestion appeared in the 1906 edition of S. S. Robison's "Manual of Wireless Telegraphy for the Use of Naval Electricians," published for use by the United States Navy. This stated that the standard visual flag signals, known as the International Code of Signals , would likely also be adopted for radio use. Therefore, the flag signal "NC" ( — · — · — · ), which stood for "In distress; want immediate assistance", would also likely become the radio distress call. SOS created in Germany A third standard resulted in the creation of the SOS distress signal. The German government issued a set of national radio regulations. These were used from April 1 , 1905 .

They introduced three new Morse code sequences, including the SOS distress signal: Ruhezeichen ("Cease-sending signal"), consisting of six dashes ( — — — — — — ). The signal was sent by shore stations to tell other local stations to stop transmitting. Suchzeichen ("Quest signal"), made of three-dits/three dahs/one-dit, all run together (· · · — — — · ). The signal was used by ships to get the attention of shore stations. Notzeichen ("Distress signal"), consisting of three-dits/three-dahs/three-dits (· · · — — — · · · ), also in a continuous sequence, "to be repeated by a ship in distress until all other stations have stopped working". SOS was developed from the general German radio call "SOE", with the 3 dits of a "S" easier to hear in static than the one dit of an "E". The string has no other meaning. It was also selected because it is easy to recognize and can be sent rapidly.

Comparing SOS (di-di-di-dah-dah-dah-di-di-dit) with the older CQD (dah-di-dah-dit dah-dah-di-dah dah-di-dit) (— ·—· /—— ·—/—· ·) it is obvious how much simpler the new code is. It would not be mistaken for CQ,either. CQ is the radio code for "calling anyone" used in casual circumstances. In 1906, the second International Radiotelegraphic Convention was held in Berlin. This convention developed many Service Regulations to be added to the main agreement, which was signed on November 3 , 1906 , and became effective on July 1 , 1908 . Article XVI of the regulations adopted Germany's Notzeichen distress signal as the international standard, reading: "Ships in distress shall use the following signal: · · · — — — · · · repeated at brief intervals".

The first ship to transmit an SOS distress call appears to have been the Cunard liner Slavonia on June 10 , 1909 , according to "Notable Achievements of Wireless" in the September, 1910 Modern Electrics. However, there was some resistance among the Marconi operators about adopting the new signal, and, as late as the April, 1912 sinking of the RMS Titanic , the ship's Marconi operators intermixed CQD and SOS distress calls. But with the need for consistency for public safety, the use of CQD appears to have generally disappeared after this point. In both the April 1 , 1905 German law, and the 1906 International regulations, the distress signal was specified as a continuous Morse code sequence of three-dits/three-dahs/three-dits, with no mention of any alphabetic equivalents.

However, in International Morse three dits make the letter S, and three dahs the letter O, and it soon became common to refer to the distress signal as "SOS." An early report on "The International Radio-Telegraphic Convention" in the January 12 , 1907 Electrical World said that "Vessels in distress use the special signal, SOS, repeated at short intervals." (In American Morse code , which was used by many coastal ships in the United States through the first part of the twentieth century, three dahs stood for the numeral "5", so in a few cases the distress signal was informally referred to as "S5S"). In contrast to CQD, which was sent as three separate letters with spaces between each letter, the SOS distress call has always been transmitted as a continuous sequence of dits-and-dahs, and not as individual letters. There was no problem as long as operators were aware that "SOS" was technically just a convenient way for remembering the proper sequence of the distress signal's total of nine dits and dahs. In later years, the number of special Morse symbols increased.

In order to designate the proper sequence of dits-and-dahs for a long special symbol, the standard practice is to list alphabetic characters which contain the same dits-and-dahs in the same order, with a bar atop the character sequence to indicate that there should not be any internal spaces in the transmission. Thus, under the modern notation, the distress signal becomes SOS. (In International Morse, VTB, IJS and SMB, among others, would also correctly translate into the · · · — — — · · · distress call sequence, but traditionally only SOS is used). SOS has also sometimes been used as a visual distress signal, consisting of three-short/three-long/three-short light flashes, or with "SOS" spelled out in individual letters, for example, stamped in a snowbank or formed out of logs on a beach. The fact that SOS can be read right side up as well as upside down became important for visual recognition if viewed from above. Famous SOS calls SS Andrea Doria Later developments Additional warning and distress signals were introduced after SOS.

On January 20 , 1914 , the London International Convention on Safety of Life at Sea adopted the Morse code signal TTT ( — — —), three letter T's (—) spaced correctly as three letters so as not to be confused with the letter O (- - -), as the "Safety Signal," used for messages to ships "involving safety of navigation and being of an urgent character." When radio transmitters that could send audio were developed, there was a need for a spoken distress phrase, and " Mayday " was adopted by the 1927 International Radio Convention as the equivalent of SOS. For TTT the equivalent audio signals are " Pan-pan " for urgency and " Securite " for navigational safety. During the Second World War , additional codes were used to include immediate details about attacks by enemy vessels, especially in the Battle of the Atlantic . The signal SSS signalled attacked by submarines, whilst RRR warned of an attack by a surface raider, QQQ warned of an unknown raider (usually an auxiliary cruiser ), and AAA indicated an attack by aircraft. They were usually sent in conjunction with the SOS distress code.

All of these codes later switched from three repeats of the letter to four repeats ("RRRR", etc.). References

Question: In Morse code, what international distress signal replaced the original CQD in 1908?
Answer: SOS